code: def save_file_list(cache_file_names):
      with open(
          os.path.join(CACHE_FOLDER, "cache_index.csv"), "w"
      ) as f:
          wr = csv.writer(f)
          wr.writerows(cache_file_names)
  
file_path: nnabla/src/nbla_utils/test/test_npy_files.py
imports: import pytest
  import numpy
  import zlib
  import csv
  import os
  from collections import OrderedDict
label_desc: Use image node_id 2 for calling a global function with example usage: save_file_list(cache_file_names) without return types